Improve Short URL HTTP error semantics (#128866)

* return 409 status code on duplicate slug

* support 404 error in by-slug resolution

* remove mime type header for errors

* harden error code type

src/plugins/share/server/url_service/error.ts

@@ -0,0 +1,15 @@
+/*
+ * Copyright Elasticsearch B.V. and/or licensed to Elasticsearch B.V. under one
+ * or more contributor license agreements. Licensed under the Elastic License
+ * 2.0 and the Server Side Public License, v 1; you may not use this file except
+ * in compliance with, at your election, the Elastic License 2.0 or the Server
+ * Side Public License, v 1.
+ */
+
+export type UrlServiceErrorCode = 'SLUG_EXISTS' | 'NOT_FOUND' | '';
+
+export class UrlServiceError extends Error {
+  constructor(message: string, public readonly code: UrlServiceErrorCode = '') {
+    super(message);
+  }
+}

src/plugins/share/server/url_service/http/short_urls/register_create_route.ts

@@ -8,6 +8,7 @@
 
 import { schema } from '@kbn/config-schema';
 import { IRouter } from 'kibana/server';
+import { UrlServiceError } from '../../error';
 import { ServerUrlService } from '../../types';
 
 export const registerCreateRoute = (router: IRouter, url: ServerUrlService) => {
@@ -41,26 +42,35 @@ export const registerCreateRoute = (router: IRouter, url: ServerUrlService) => {
       if (!locator) {
         return res.customError({
           statusCode: 409,
-          headers: {
-            'content-type': 'application/json',
-          },
           body: 'Locator not found.',
         });
       }
 
-      const shortUrl = await shortUrls.create({
-        locator,
-        params,
-        slug,
-        humanReadableSlug,
-      });
+      try {
+        const shortUrl = await shortUrls.create({
+          locator,
+          params,
+          slug,
+          humanReadableSlug,
+        });
 
-      return res.ok({
-        headers: {
-          'content-type': 'application/json',
-        },
-        body: shortUrl.data,
-      });
+        return res.ok({
+          headers: {
+            'content-type': 'application/json',
+          },
+          body: shortUrl.data,
+        });
+      } catch (error) {
+        if (error instanceof UrlServiceError) {
+          if (error.code === 'SLUG_EXISTS') {
+            return res.customError({
+              statusCode: 409,
+              body: error.message,
+            });
+          }
+        }
+        throw error;
+      }
     })
   );
 };

src/plugins/share/server/url_service/http/short_urls/register_resolve_route.ts

@@ -8,6 +8,7 @@
 
 import { schema } from '@kbn/config-schema';
 import { IRouter } from 'kibana/server';
+import { UrlServiceError } from '../../error';
 import { ServerUrlService } from '../../types';
 
 export const registerResolveRoute = (router: IRouter, url: ServerUrlService) => {
@@ -26,15 +27,28 @@ export const registerResolveRoute = (router: IRouter, url: ServerUrlService) =>
     router.handleLegacyErrors(async (ctx, req, res) => {
       const slug = req.params.slug;
       const savedObjects = ctx.core.savedObjects.client;
-      const shortUrls = url.shortUrls.get({ savedObjects });
-      const shortUrl = await shortUrls.resolve(slug);
 
-      return res.ok({
-        headers: {
-          'content-type': 'application/json',
-        },
-        body: shortUrl.data,
-      });
+      try {
+        const shortUrls = url.shortUrls.get({ savedObjects });
+        const shortUrl = await shortUrls.resolve(slug);
+
+        return res.ok({
+          headers: {
+            'content-type': 'application/json',
+          },
+          body: shortUrl.data,
+        });
+      } catch (error) {
+        if (error instanceof UrlServiceError) {
+          if (error.code === 'NOT_FOUND') {
+            return res.customError({
+              statusCode: 404,
+              body: error.message,
+            });
+          }
+        }
+        throw error;
+      }
     })
   );
 };

src/plugins/share/server/url_service/index.ts

@@ -10,3 +10,4 @@ export * from './types';
 export * from './short_urls';
 export { registerUrlServiceRoutes } from './http/register_url_service_routes';
 export { registerUrlServiceSavedObjectType } from './saved_objects/register_url_service_saved_object_type';
+export * from './error';

src/plugins/share/server/url_service/short_urls/short_url_client.test.ts

@@ -12,6 +12,7 @@ import { LegacyShortUrlLocatorDefinition } from '../../../common/url_service/loc
 import { MemoryShortUrlStorage } from './storage/memory_short_url_storage';
 import { SerializableRecord } from '@kbn/utility-types';
 import { SavedObjectReference } from 'kibana/server';
+import { UrlServiceError } from '../error';
 
 const setup = () => {
   const currentVersion = '1.2.3';
@@ -125,7 +126,7 @@ describe('ServerShortUrlClient', () => {
             url: '/app/test#foo/bar/baz',
           },
         })
-      ).rejects.toThrowError(new Error(`Slug "lala" already exists.`));
+      ).rejects.toThrowError(new UrlServiceError(`Slug "lala" already exists.`, 'SLUG_EXISTS'));
     });
 
     test('can automatically generate human-readable slug', async () => {

src/plugins/share/server/url_service/short_urls/short_url_client.ts

@@ -18,6 +18,7 @@ import type {
   ShortUrlData,
   LocatorData,
 } from '../../../common/url_service';
+import { UrlServiceError } from '../error';
 import type { ShortUrlStorage } from './types';
 import { validateSlug } from './util';
 
@@ -74,7 +75,7 @@ export class ServerShortUrlClient implements IShortUrlClient {
     if (slug) {
       const isSlugTaken = await storage.exists(slug);
       if (isSlugTaken) {
-        throw new Error(`Slug "${slug}" already exists.`);
+        throw new UrlServiceError(`Slug "${slug}" already exists.`, 'SLUG_EXISTS');
       }
     }
 

src/plugins/share/server/url_service/short_urls/storage/saved_object_short_url_storage.ts

@@ -9,6 +9,7 @@
 import type { SerializableRecord } from '@kbn/utility-types';
 import { SavedObject, SavedObjectReference, SavedObjectsClientContract } from 'kibana/server';
 import { ShortUrlRecord } from '..';
+import { UrlServiceError } from '../..';
 import { LEGACY_SHORT_URL_LOCATOR_ID } from '../../../../common/url_service/locators/legacy_short_url_locator';
 import { ShortUrlData } from '../../../../common/url_service/short_urls/types';
 import { ShortUrlStorage } from '../types';
@@ -161,7 +162,7 @@ export class SavedObjectShortUrlStorage implements ShortUrlStorage {
     });
 
     if (result.saved_objects.length !== 1) {
-      throw new Error('not found');
+      throw new UrlServiceError('not found', 'NOT_FOUND');
     }
 
     const savedObject = result.saved_objects[0] as ShortUrlSavedObject;

test/api_integration/apis/short_url/create_short_url/main.ts

@@ -131,8 +131,8 @@ export default function ({ getService }: FtrProviderContext) {
           slug,
         });
 
-        expect(response1.status === 200).to.be(true);
-        expect(response2.status >= 400).to.be(true);
+        expect(response1.status).to.be(200);
+        expect(response2.status).to.be(409);
       });
     });
   });

test/api_integration/apis/short_url/get_short_url/main.ts

@@ -23,6 +23,12 @@ export default function ({ getService }: FtrProviderContext) {
       expect(response2.body).to.eql(response1.body);
     });
 
+    it('returns 404 error when short URL does not exist', async () => {
+      const response = await supertest.get('/api/short_url/NotExistingID');
+
+      expect(response.status).to.be(404);
+    });
+
     it('supports legacy short URLs', async () => {
       const id = 'abcdefghjabcdefghjabcdefghjabcdefghj';
       await supertest.post('/api/saved_objects/url/' + id).send({

test/api_integration/apis/short_url/resolve_short_url/main.ts

@@ -26,6 +26,12 @@ export default function ({ getService }: FtrProviderContext) {
       expect(response2.body).to.eql(response1.body);
     });
 
+    it('returns 404 error when short URL does not exist', async () => {
+      const response = await supertest.get('/api/short_url/_slug/not-existing-slug');
+
+      expect(response.status).to.be(404);
+    });
+
     it('can resolve a short URL by its slug, when slugs are similar', async () => {
       const rnd = Math.round(Math.random() * 1e6) + 1;
       const now = Date.now();